Anti-peptic ulcer drugs (APUDs) such as proton pump inhibitors (PPI), H2 receptor antagonists (H2A), antacids are widely prescribed. This study is aimed to describe the utilisation pattern of APUDs based on WHO Defined Daily Dose (DDD) and identify most commonly used APUD in the selected hospital. A retrospective study was carried out in outpatient of the selected hospital for year 2017. Sample size was calculated using Raosoft. DDD of APUDs and direct drug cost were calculated. Data were collected through electronic medical record by retrieving patients’ registration number. Inclusion criteria were patients above 18 years old and APUDs prescribed for gastrointestinal related indications. A total of 160 prescriptions were randomly selected for data analysis. Based on the DDD calculated, Rabeprazole 20mg was most prescribed drug among PPI (n=33), while Maalox is most prescribed drug among the antacids (n=23). Based on the DDD calculated, Pantoprazole 20mg recorded highest rates per user per day about 1.26 DDD / user / day while antacids, Actal reported highest usage rate with 7.11 DDD / user / day. Besides, there are 5.4 days supplied per user for this drug. Dexlansoprazole 60mg is the most expensive drug among all the PPI listed in hospital formulary. It has 18.5 days supplied/user, which is the second shortest duration of treatment among all the other PPIs. In contrast, omeprazole 20mg is the lowest cost PPI but the duration supplied per user is longer resulting in higher total cost of therapy. In conclusion, PPIs were the most commonly prescribed.